Control of particulate flowback in subterranean wells

ABSTRACT

The present invention provides a method of treating a subterranean formation with a particulate laden fluid whereby particulate flowback is reduced or prevented. The method includes the steps of providing a fluid suspension including a mixture of a particulate upon admixture therewith, pumping the suspension into a subterranean formation and depositing the mixture within the formation whereby the tackifying compound retards movement of at least a portion of the particulate within the formation upon flow of fluids from the subterranean formation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application is a Continuation-in-part of U.S. applicationSer. No. 08/510,399, filed Aug. 2, 1995, now U.S. Pat. No. 5,582,249,and a Continuation-in-Part of U.S. application Ser. No. 08/412,668,filed Mar. 29, 1995, now U.S. Pat. No. 5,501,274.

BACKGROUND OF THE INVENTION

1. Field Of The Invention

This invention relates to means for recovering hydrocarbons from asubterranean formation and more particularly to a method and means forcontrolling particulate solids transport during the production ofhydrocarbons from a subterranean formation.

2. Brief Description Of The Prior Art

Transport of particulate solids during the production of hydrocarbonsfrom a subterranean formation is a continuing problem. The transportedsolids can erode or cause significant wear in the hydrocarbon productionequipment used in the recovery process. The solids also can clog or plugthe wellbore thereby limiting or completely stopping fluid production.Further, the transported particulates must be separated from therecovered hydrocarbons adding further expense to the processing.

The particulates which are available for transport may be present due toan unconsolidated nature of a subterranean formation and/or as a resultof well treatments placing particulates in a wellbore or formation, suchas, by gravel packing or propped fracturing.

In the treatment of subterranean formations, it is common to placeparticulate materials as a filter medium and/or a proppant in the nearwellbore area and in fractures extending outwardly from the wellbore. Infracturing operations, proppant is carried into fractures created whenhydraulic pressure is applied to these subterranean rock formations to apoint where fractures are developed. Proppant suspended in a viscosifiedfracturing fluid is carried outwardly away from the wellbore within thefractures as they are created and extended with continued pumping. Uponrelease of pumping pressure, the proppant materials remain in thefractures holding the separated rock faces in an open position forming achannel for flow of formation fluids back to the wellbore.

Proppant flowback is the transport of proppants back into the wellborewith the production of formation fluids following fracturing. Thisundesirable result causes undue wear on production equipment, the needfor separation of solids from the produced hydrocarbons and occasionallyalso decreases the efficiency of the fracturing operation since theproppant does not remain within the fracture and may limit the width orconductivity of the created flow channel. Proppant flowback often may bea aggravated by what is described as "aggressive" flowback of the wellafter a stimulation treatment. Aggressive flowback generally entailsflowback of the treatment fluid at a rate of from about 0.001 to about0.1 barrels per minute (BPM) per perforation of the treatment fluidswhich were introduced into the subterranean formation. Such flowbackrates accelerate or force closure of the formation upon the proppantintroduced into the formation. The rapid flowrate can result in largequantities of the proppant flowing back into the wellbore before closureoccurs or where inadequate bridging within the formation occurs. Therapid flowback is highly desirable for the operator as it returns awellbore to production of hydrocarbons significantly sooner than wouldresult from other techniques.

Currently, the primary means for addressing the proppant flowbackproblem is to employ resin-coated proppants or resin consolidation ofthe proppant which are not capable of use in aggressive flowbacksituations. Further, the cost of resin-coated proppant is high, and istherefore used only as a tail-in in the last five to twenty five percentof the proppant placement. Resin-coated proppant is not always effectivesince there is some difficulty in placing it uniformly within thefractures and, additionally, the resin coating can have a deleteriouseffect on fracture conductivity. Resin coated proppant also may interactchemically with common fracturing fluid crosslinking systems such asguar or hydroxypropylguar with organo-metallics or borate crosslinkers.This interaction results in altered crosslinking and/or break times forthe fluids thereby affecting placement. Another means showing reasonableeffectiveness has been to gradually release fracturing pressure once thefracturing operation has been completed so that fracture closurepressure acting against the proppant builds slowly allowing the proppantparticles to stabilize before flowback of the fracturing fluid and thebeginning of hydrocarbon production. Such slow return is undesirable,however, since it reduces the production from the wellbore until thetreatment fluid is removed.

In unconsolidated formations, it is common to place a filtration bed ofgravel in the near-wellbore area in order to present a physical barrierto the transport of unconsolidated formation fines with the productionof hydrocarbons. Typically, such so-called "gravel packing operations"involve the pumping and placement of a quantity of gravel and/or sandhaving a mesh size between about 10 and 60 mesh on the U.S. StandardSieve Series into the unconsolidated formation adjacent to the wellbore.It is sometimes also desirable to bind the gravel particles together inorder to form a porous matrix through which formation fluids can passwhile straining out and retaining the bulk of the unconsolidated sandand/or fines transported to the near wellbore area by the formationfluids. The gravel particles may constitute a resin-coated gravel whichis either pre-cured or can be cured by an overflush of a chemicalbinding agent once the gravel is in place. It has also been known to addvarious hardenable binding agents or hardenable adhesives directly to anoverflush of unconsolidated gravel in order to bind the particlestogether.

U.S. Pat. Nos. 5,330,005, 5,439,055 and 5,501,275 disclose a method forovercoming the difficulties of resin coating proppants or gravel packsby the incorporation of a fibrous material in the fluid with which theparticulates are introduced into the subterranean formation. The fibersgenerally have a length ranging upwardly from about 2 millimeters and adiameter of from about 6 to about 200 microns. Fibrillated fibers ofsmaller diameter also may be used. The fibers are believed to act tobridge across constrictions and orifices in the proppant pack and form amat or framework which holds the particulates in place thereby limitingparticulate flowback. The fibers typically result in a 25 percent orgreater loss in permeability of the proppant pack that is created incomparison to a pack without the fibers.

While this technique may function to limit some flowback, it fails tosecure the particulates to one another in the manner achieved by use ofresin coated particulates.

U.S. Pat. No. 5,501,274 discloses a method for reducing proppantflowback by the incorporation of thermoplastic material in particulate,ribbon or flake form with the proppant. Upon deposition of the proppantand thermoplastic material in the formation, the thermoplastic materialsoftens and causes particulates adjacent the material to adhere to thethermoplastic creating agglomerates. The agglomerates then bridge withthe other agglomerates and other particulates to prevent flowback fromthe formation.

It would be desirable to provide a method which will bind greaternumbers of particles of the particulate to one another wherebyagglomerates may be formed which would further assist in preventingmovement or flowback of particulates from a wellbore or formationwithout significantly reducing the permeability of the particulate packduring aggressive flowback of treatment fluids.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method and fluid for treating asubterranean formation and a resultant porous particulate pack thatinhibits the flow of particulates back through the wellbore with theproduction of hydrocarbons without significant effects upon thepermeability of the particulate pack.

In accordance with the invention, a method of treating a subterraneanformation penetrated by a wellbore is provided comprising the steps ofproviding a fluid suspension including a mixture of particulate materialand another material comprising a liquid or solution of a tackifyingcompound, which coats at least a portion of the particulate uponadmixture therewith, pumping the fluid suspension including the coatedparticulate through the wellbore and depositing the mixture in theformation. Upon deposition of the coated material mixture in theformation the coating causes particulate adjacent the material to adhereto the coated material thereby creating agglomerates which bridgeagainst other particles in the formation to prevent particulateflowback.

The coated material is effective in inhibiting the flowback ofparticulate in a porous pack having a size ranging from about 2 to about400 mesh in intimate admixture with the tackifying compound coatedparticulates.

The coated material is effective in consolidating particulate in theform of agglomerates in a formation as a result of a fracturing orgravel packing treatment performed on a subterranean formation duringaggressive flowback of the treatment fluid.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 provides a schematic illustration of the test apparatus utilizedto determine the critical resuspension velocity for a coated substratematerial.

FIG. 2 provides a schematic illustration of additional unconfined flowcell test apparatus.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a liquid or solution of atackifying compound is incorporated in an intimate mixture with aparticulate material such as conventional proppants or gravel packingmaterials and introduced into a subterranean formation.

As used in this specification, the term "intimate mixture" will beunderstood to mean a substantially uniform dispersion of the componentsin the mixture. The term "simultaneous mixture" will be understood tomean a mixture of components that are blended together in the initialsteps of the subterranean formation treatment process or the preparationfor the performance of the treatment process.

The coated particulate or proppant material may comprise substantiallyany substrate material that does not undesirable chemically interactwith other components used in treating the subterranean formation. Thematerial may comprise sand, ceramics, glass, sintered bauxite, resincoated sand, resin beads, metal beads and the like. The coated materialalso may comprise an additional material that is admixed with aparticulate and introduced into a subterranean formation to reduceparticulate flowback. In this instance the additional substrate materialmay comprise glass, ceramic, carbon composites, natural or syntheticpolymers or metal and the like in the form of fibers, flakes, ribbons,beads, shavings, platelets and the like. In this instance, theadditional substrate material generally will be admixed with theparticulate in an amount of from about 0.1 to about 5 percent by weightof the particulate.

The tackifying compound comprises a liquid or a solution of a compoundcapable of forming at least a partial coating upon the substratematerial with which it is admixed prior to or subsequent to placement inthe subterranean formation. In some instances, the tackifying compoundmay be a solid at ambient surface conditions and upon initial admixingwith the particulate and after heating upon entry into the wellbore forintroduction into the subterranean formation become a melted liquidwhich at least partially coats a portion of the particulate. Compoundssuitable for use as a tackifying compound comprise substantially anycompound which when in liquid form or in a solvent solution will form anon-hardening coating, by themselves, upon the particulate and willincrease the continuous critical resuspension velocity of theparticulate when contacted by a stream of water as hereinafter describedin Example I by at least about 50 percent over the particulate alonewhen present in a 0.5 percent by weight active material concentrationand increase the initial critical resuspension velocity by at leastabout 50 percent over the particulate alone. Preferably, the continuouscritical resuspension velocity is increased by at least 100 percent overparticulate alone and most preferably at least about 150 percent overparticulate alone and the initial critical resuspension velocity isincreased by at least 75 percent and most preferably at least 100percent over particulate alone. A particularly preferred group oftackifying compounds comprise polyamides which are liquids or in solventsolution at the temperature of the subterranean formation to be treatedsuch that the polyamides are, by themselves, non-hardening when presenton the particulates introduced into the subterranean formation. Aparticularly preferred product is a condensation reaction productcomprised of commercially available polyacids and a polyamine. Suchcommercial products include compounds such as mixtures of C₃₆ dibasicacids containing some trimer and higher oligomers and also small amountsof monomer acids which are reacted with polyamines. Other polyacidsinclude trimer acids, synthetic acids produced from fatty acids, maleicanhydride and acrylic acid and the like. Such acid compounds areavailable from companies such as Witco, Union Camp, Chemtall, and EmeryIndustries. The reaction products are available from, for example,Champion Chemicals, Inc. and Witco.

In general, the polyamides of the present invention are commerciallyproduced in batchwise processing of polyacids predominately having twoor more acid functionalities per molecule with a polyamine. As is wellknown in the manufacturing industry, the polyacids and polyfunctionalamines are introduced into a reactor where, with agitation, the mildlyexothermic formation of the amide salt occurs. After mixing, heat isapplied to promote endothermic dehydration and formation of the polymermelt by polycondensation. The water of reaction is condensed and removedleaving the polyamide. The molecular weight and final properties of thepolymer are controlled by choice and ratio of feedstock, heating rate,and judicious use of monofunctional acids and amines to terminate chainpropagation. Generally an excess of polyamine is present to preventrunaway chain propagation. Unreacted amines can be removed bydistillation, if desired. Often a solvent, such as an alcohol, isadmixed with the final condensation reaction product to produce a liquidsolution that can readily be handled. The condensation reactiongenerally is accomplished at a temperature of from about 225° F. toabout 450° F. under a nitrogen sweep to remove the condensed water fromthe reaction. The polyamines can comprise, for example, ethylenediamine,diethylenetriamine, triethylene tetraamine, amino ethyl piperazine andthe like.

The polyamides can be converted to quaternary compounds by reaction withmethylene chloride, dimethyl sulfate, benzylchloride, diethyl sulfateand the like. Typically the quaternization reaction would be effected ata temperature of from about 100° to about 200° F. over a period of fromabout 4 to 6 hours.

The quaternization reaction may be employed to improve the chemicalcompatibility of the tackifying compound with the other chemicalsutilized in the treatment fluids. Quaternization of the tackifyingcompound can reduce effects upon breakers in the fluids and reduce orminimize the buffer effects of the compounds when present in variousfluids.

Additional compounds which may be utilized as tackifying compoundsinclude liquids and solutions of, for example, polyesters andpolycarbamates, natural resins such as shellac and the like.

The tackifying compound is admixed with the particulate in an amount offrom about 0.1 to about 3.0 percent active material by weight of thecoated particulate. It is to be understood that larger quantities may beused, however, the larger quantities generally do not significantlyincrease performance and could undesirably reduce the permeability ofthe particulate pack. Preferably, the tackifying compound is admixedwith the particulate introduced into the subterranean formation in anamount of from about 0.25 to about 2.0 percent by weight of the coatedparticulate.

When the tackifying compound is utilized with another material that isto be admixed with the particulate and which is to be at least partiallycoated with the tackifying compound, such as glass fibers or the like,the compound is present in an amount of from about 10 to about 250percent active material by weight of the glass fibers or other addedmaterial and generally from about 0.1 to about 3 percent active materialby weight of the quantity of particulate with which the coated materialis intimately admixed. Preferably the tackifying compound is present inan amount of from about 50 to about 150 percent of the material which isto be at least partially coated with the tackifying compound and thenadded to the particulate. At least a portion of the tackifying compoundintroduced with the additional material will contact and coat at least aportion of the particulate with which it is admixed.

The liquid or solution of tackifying compound interacts mechanicallywith the particles of particulate introduced into the subterraneanformation to limit or prevent the flowback of particulates to thewellbore.

The liquid or solution of tackifying compound generally is incorporatedwith the particulate in any of the conventional fracturing or gravelpacking fluids comprised of an aqueous fluid, an aqueous foam, ahydrocarbon fluid or an emulsion, a viscosifying agent and any of thevarious known breakers, buffers, surfactants, clay stabilizers or thelike.

Generally the tackifying compound may be incorporated into fluids havinga pH in the range of from about 3 to about 12 for introduction into asubterranean formation. The compounds are useful in reducing particulatemovement within the formation at temperatures from about ambient to inexcess of 275° F. It is to be understood that not every tackifyingcompound will be useful over the entire pH or temperature range butevery compound is useful over at least some portion of the range andindividuals can readily determine the useful operating range for variousproducts utilizing well known tests and without undue experimentation.

The liquid or solution of tackifying compound generally is incorporatedwith the particulate as a simultaneous mixture by introduction into thefracturing or gravel packing fluid along with the particulate.Fracturing fluids are introduced into the subterranean formation at arate and pressure sufficient to create at least one fracture in theformation into which particulate then is introduced to prop the createdfracture open to facilitate hydrocarbon production. Gravel packingtreatments generally are performed at lower rates and pressures wherebythe fluid can be introduced into a formation to create a controlledparticule size pack surrounding a screen positioned in the wellborewithout causing fracturing of the formation. The particulate packsurrounding the wellbore then functions to prevent fines or formationparticulate migration into the wellbore with the production ofhydrocarbons from the subterranean formation. The tackifying compoundmay be introduced into the fluid before, after or simultaneously withintroduction of the particulate into the fluid. The liquid or solutionmay be incorporated with the entire quantity of particulate introducedinto the subterranean formation or it may be introduced with only aportion of the particulate, such as in the final stages of the treatmentto place the intimate mixture in the formation in the vicinity of thewellbore. For example, the tackifying compound may be added to only thefinal 20 to 30 percent of the particulate laden fluid introduced intothe formation. In this instance, the intimate mixture will form atail-in to the treatment which upon interaction within the formationwith the particulate will cause the particles to bridge on theagglomerates formed therein and prevent movement of the particles intothe wellbore with any produced fluids. The tackifying compound may beintroduced into the blender or into any flowline in which it willcontact the material to be at least partially coated by the compound.The compound may be introduced with metering pumps or the like prior toentry of the treatment fluid into the subterranean formation.

In an alternate embodiment, the particulate may be premixed with thetackifying compound prior to admixing with a treatment fluid for use ina subterranean formation.

To further illustrate the present invention and not by way oflimitation, the following examples are provided.

EXAMPLE I

The evaluation of a liquid or solution of a compound for use as atackifying compound is accomplished by the following test. A criticalresuspension velocity is first determined for the material upon whichthe tackifying compound is to be coated. Referring now to FIG. 1, a testapparatus is illustrated for performing the test. The apparatuscomprises a 1/2" glass tee 10 which is connected to an inlet source 12of water and an outlet 14 disposal line is blocked to fluid flow. Awater slurry of particulate is aspirated into the tee 10 through inlet12 and collected within portion 16 by filtration against a screen 18.When portion 16 of tee 10 is full, the vacuum source is removed and aplug 20 is used to seal the end of portion 16. The flow channel frominlet 12 to outlet 14 then is swabbed clean and a volumetricallycontrolled pump, such as a "MOYNO" pump, is connected to inlet 12 and acontrolled flow of water is initiated. The velocity of the fluid isslowly increased through inlet 12 until the first particule ofparticulate material is picked up by the flowing water stream. Thisdetermines the baseline for the starting of the resuspension velocity.The flow rate then is further increased until the removal of particlesbecomes continuous. This determines the baseline for the continuousresuspension velocity. The test then is terminated and the apparatus isrefilled with particulate having a coating corresponding to about 0.5percent active material by weight of the particulate applied thereto.Similar trends generally are seen in the results when the concentrationstested are from about 0.1 to about 3 percent, however, the 0.5 percentlevel which is within the preferred application range is preferred forstandardization of the procedure. The test is repeated to determine thestarting point of particulate removal and the velocity at which removalbecomes continuous. The percent of velocity increase (or decrease) thenis determined based upon the initial or continuous baseline value. Theresults of several tests employing the preferred polyamide of thepresent invention, and conventional epoxy and phenolic resins known foruse in consolidation treatments in subterranean formations with 12/20and 20/40 mesh sand are set forth below in Table I.

                  TABLE I                                                         ______________________________________                                                         Coating Agent,                                                                            Percent Of Velocity                              Test  Particulate                                                                              % V/Wt      Change At                                        No.   Size       Particulate Starting                                                                             Continuous                                ______________________________________                                        1     20/40/mesh none         0      0                                              sand                                                                    2     20/40 mesh 1/2 percent 192    222                                             sand       polyamide                                                    3     20/40 mesh 1 percent   271    391                                             sand       polyamide                                                    4     20/40 mesh 1/2 percent   -0.5   -6.5                                          sand       phenolic                                                     5     20/40 mesh 1 percent   -9       -6.8                                          sand       phenolic                                                     6     20/40 mesh 1/2 percent -9       -1.2                                          sand       epoxy                                                        7     20/40 mesh 1 percent     5.2    12.2                                          sand       epoxy                                                        8     12/20 mesh 1/2 percent 228    173                                             sand       polyamide                                                    9     12/20 mesh 1 percent   367    242                                             sand       polyamide                                                    10    12/20 mesh 1/2 percent 42     22                                              sand       phenolic                                                     11    12/20 mesh 1 percent   42     13                                              sand       phenolic                                                     12    12/20 mesh 1/2 percent 48     30                                              sand       epoxy                                                        13    12/20 mesh 1 percent   38     15                                              sand       epoxy                                                        ______________________________________                                    

The data clearly illustrates the substantial increase in the criticalresuspension velocity of a particulate coated with the tackifyingcompound in comparison to other known formation consolidation agentswhich require hardening to be effective.

EXAMPLE II

A series of tests were performed using the apparatus in FIG. 2 todetermine the effect of the addition of the tackifying compound to aparticulate admixed with another material comprising glass fibers. Theparticulate comprised 20/40 mesh sand. The glass fibers had a diameterof about 12 microns and a length of about 1/2 inch. The mixing fluidcomprised water or a gelled fluid containing 25 pounds of guar per 1000gallons of fluid. In accordance with the test procedure, 450 grams of20/40 sand were mixed with 1% by weight of glass fibers with a mixingfluid and the resulting slurry was aspirated through a conduit 31 intotest cell 30 to form a pack within cell 30 against a screen 32 adjacentconduit 33. Cell 30 had an interior diameter of approximately 15/8 inchand was approximately 10 inches in length. After the pack was formed, aflow of water was initiated through conduit 33 into cell 30 and outthrough a replaceable washer 34 located adjacent conduit 31. Washer 34had a 5/8 inch diameter hole to simulate a wellbore casing perforation.The flow rate of the water was continually increased until the sand packfailed and sand flowed through the perforation. The glass fibercontaining pack failed at a flow rate of 51.4 barrels per day whengelled fluid was used as the mix fluid and 41.7 barrels per day whenwater was used as the mix fluid. The tests were repeated including atackifying compound in an amount of 0.5% V/wt of sand. The tackifyingcompound comprised a polyamide. The tackifying compound/glass fibercontaining pack when gelled fluid was used as the mix fluid failed at69.6 barrels per day and the pack prepared with water failed at 61.9barrels per day.

The results clearly demonstrate the substantial increase in formationfluid flow that can be achieved from a subterranean formation containingparticulate including both the fibers and the tackifying compound overthe fibers alone without undesirable particulate production from theformation.

EXAMPLE III

To illustrate the effectiveness of the method of the present inventiontwo gas wells approximately one mile apart in the Chase Formation weretreated on the same day. One well utilized the method of the presentinvention employing a tackifying compound and the other well utilizedsubstantially the same fluids, proppant quantity and pumping schedulewithout the tackifying compound. The approximate depth of the wells were2800 feet containing 5 1/2" casing cemented to the surface. The wellswere plugged with sand prior to the treatment to a depth of about 2700feet. The fracturing treatments involved a 2000 gallon prepad of treatedwater, a 12000 gallon pad pumped at 35 barrels per minute utilizing aborate crosslinked guar-containing fluid, a 21000 gallon fracturingtreatment pumped at 30 barrels per minute containing 12/20 mesh sandintroduced in a ramped schedule from 1 to 8 pounds per gallon for atotal sand content of about 120,000 pounds. The fracturing treatmentutilized a borate crosslinked guar-containing fluid including in onewell 0.1 gal tackifying compound per 100 pounds of sand. The wells wereflushed with 1000 gallons of fluid after the fracturing treatment. Thetreatment fluids also contained the typical biocides, breakers andsurfactants utilized in conventional fracturing fluids. Thereafter, thewells were cleaned out and the volumes of sand determined as follows:

Well without tackifying compound-Tag sand in wellbore at 2710 feet andclean out to bottom of hole at 2818 feet with sand pump. Total sandrecovered to clean wellbore was 491 gallons. This was over three timesthe tubing volume originally containing sand thereby indicatingsignificant immediate sand flowback. The well was blown down for 45minutes after which an additional 292 gallons of sand were recoveredfrom the wellbore. Over the next three days an additional 168 gallons ofsand were recovered and the well continued to produce sand as treatmentfluid was recovered by pumping the wellbore. Total sand produced afterwellbore cleanout was 881 gallons.

Well with tackifying compound-Tag sand at 2700 feet and clean out withsand pump to 2796 feet.

Total sand recovered to clean wellbore was 127 gallons.

The well was blown down for 20 minutes after which 1 gallon of and wasrecovered from the wellbore. Over the next two days an additional 5gallons of sand was recovered as treatment fluid was recovered from thewellbore by pumping.

The treatment utilizing the method of the present invention resulted inapproximately 6 gallons of sand returning to the wellbore after thetreatment. The treatment performed without the tackifying compoundresulted in excess of 881 gallons of sand returning to the wellbore.These results clearly illustrate the benefits to be derived from use ofthe present invention in reduced rig time for sand recovery from thetreated well versus the untreated well. Further benefits would resultfrom reduced repair costs from produced sand induced damage to pumps andother surface equipment.

While the present invention has been described with regard to that whichis currently considered to comprise the preferred embodiments of theinvention, other embodiments have been suggested and still otherembodiments will occur to those individuals skilled in the art uponreceiving the foregoing specification. It is intended that all suchembodiments shall be included within the scope of the present inventionas defined by the claims appended hereto.

What is claimed is:
 1. A method of treating a subterranean formationcomprising the steps of:introducing a particulate-containing fluid intoa fracture created in a subterranean formation; admixing with at least aportion of said particulate in said fluid suspension a liquid orsolution of a tackifying compound whereby at least a portion of saidparticulate is at least partially coated by said compound such that thecritical resuspension velocity of said at least partially coatedparticulate is increased by at least about 50 percent when tested at alevel of 0.5% active material by weight over said particulate alone withwater; depositing the tackifying compound coated particulate in thefracture in said subterranean formation; and forcing closure of saidfracture upon said coated particulate by rapidly flowing back fluid fromthe formation whereby the tackifying compound coated particulate retardsmovement of at least a portion of the particulate within said formationduring said forced closure.
 2. The method of claim 1 wherein saidtackifying compound comprises predominately a condensation reactionproduct of a dimer acid containing some trimer and higher oligomers andsome monomer acids with a polyamine.
 3. The method of claim 2 whereinsaid polyamine comprises at least one member selected from the group ofethylenediamine, diethylenetriamine, triethylenetetraamine,tetraethylene pentaamine and aminoethylpiperazine.
 4. The method ofclaim 1 wherein said tackifying compound comprises a liquid or solutionof a polyamide.
 5. A method of treating a subterranean formationpenetrated by a wellbore having perforations therein comprising thesteps of:introducing a treatment fluid into a subterranean formationthrough said perforations at a rate and pressure sufficient to create atleast one fracture in said subterranean formation; admixing with atleast a portion of said fluid, a particulate which is introduced intoand deposited within said fracture; admixing with at least a portion ofsaid particulate a liquid or solution of a tackifying compound wherebyat least a portion of said particulate is at least partially coated bysaid compound such that the critical resuspension velocity of said atleast partially coated particulate is increased by at least about 50percent when tested at a level of 0.5% active material by weight oversaid particulate alone with water; depositing the tackifying compoundcoated particulate in the subterranean formation; and flowing back fluidfrom the formation at a rate in excess of about 0.001 barrels per minuteper perforation whereby the tackifying compound coated particulateretards movement of at least a portion of the particulate within saidformation.
 6. The method of claim 5 wherein said tackifying compound isadmixed with said particulate in an amount of from about 0.1 to about3.0 percent by weight of said particulate.
 7. The method of claim 5wherein said tackifying compound is admixed with said particulate in anamount of from about 0.25 to about 2 percent by weight of saidparticulate.
 8. The method of claim 5 wherein said coated particulatehas a critical resuspension velocity in excess of 100 percent over saidparticulate alone.
 9. The method of claim 5 wherein said tackifyingcompound comprises a liquid or solution of a polyamide.
 10. The methodof claim 5 wherein said tackifying compound comprises predominately acondensation reaction product of a dimer acid containing some trimer andhigher oligomers and some monomer acids with a polyamine.
 11. The methodof claim 10 wherein said polyamine comprises at least one memberselected from the group of ethylenediamine, diethylenetriamine,triethylenetetraamine, tetraethylene pentaamine andaminoethylpiperazine.
 12. The method of claim 10 wherein said tackifyingcompound has been quaternized.
 13. The method of claim 5 wherein saidparticulate comprises at least one member selected from the groupconsisting of sand, ceramic particles, resin coated sand, hardened resinbeads, sintered bauxite, metal particles and glass particles.
 14. Amethod of treating a subterranean formation penetrated by a wellborecomprising the steps of:providing a fluid suspension including a mixtureof a particulate material and another material selected from the groupof particles comprising metal, natural or synthetic polymers, ceramicsand glass which are at least partially coated with a liquid or solutionof a tackifying compound; introducing the fluid suspension into asubterranean formation through a wellbore; depositing the fluidsuspension in the formation; and flowing back fluid from the formationwhereby the tackifying compound material retards movement of at least aportion of the particulate material from the formation into thewellbore.
 15. The method of claim 14 wherein said another material is inthe form of fibers, beads, ribbons, flakes, platelets or shavings. 16.The method of claim 14 wherein said another material is present in anamount of from about 0.1 to about 5% by weight of the particulatematerial.
 17. The method of claim 14 wherein said tackifying compound ispresent in an amount of from about 0.1 to about 3% by weight of saidparticulate.
 18. The method of claim 14 wherein said tackifying compoundcomprises a liquid or solution of a polyamide.
 19. The method of claim14 wherein said tackifying compound comprises predominately acondensation reaction product of a dimer acid containing some trimer andhigher oligomers and some monomer acids and a polyamine.
 20. The methodof claim 14 wherein said tackifying compound comprises at least onemember selected from the group of a liquid or solution of a polyester, apolycarbamate and a natural resin.